Elderly Narcissists: Any Hope for Improvement?

From what I've read, the jury is still out regarding whether a narcissist gets better or worse with age.
Based on my personal experience, my elderly narcissist "seems" better at times. However, just when I'm about to rejoice over her change for the better, and thank God for it, she will act out once again and throw me for another loop.
Before going into more details on my view of elderly narcissists, I want to give some background history of my dealings with narcissists.
My mother is a narcissist. She was a "queen" narcissist during her younger years and in her late 60's she transformed into a "hermit" type of narcissist. She stayed home, was glad for her isolation and demanded that we her "subjects" would wait on her hand and foot. But before this, when I was a small child, I lived in fear of my mother constantly. She cared only about her needs and what it would take to get them met and that usually involved using people. I always felt like I was in her way and as though I was a type of inanimate object. She would say things to belittle me. I could walk into the room looking like a million bucks and she would tell me how horrible my hair was or badger me about a wrinkle in my shirt. These frequent nit-picking sessions bothered me but I learned to live with them. She wanted me to fight with her, she wanted to get under my skin. I learned that when she would go full steam with the put-downs, I would respond with the following: "Oh really? Well, I'll have to fix that" (regarding the shirt wrinkle or my hair out of place). I am a Christian and had I not known God , Jesus Christ, and the Holy Spirit from a young age, it would have definitely put me at a disadvantage in dealing with my narcissistic mother.
You who have dealt with narcissists will understand that there is no "cure" for them so to speak. Over the years I had tried being super-nice to her. Treating her that way made her run over me all the more. I prayed for her, I took care of her every need and that didn't do any good. I have ALWAYS held out hope for my mother while constantly being on guard so as to not let her damage me and the ones I love. I cannot tell you the number of times I flung the phone across the room after having talked with her. I had to watch myself over the years because dealing with a narcissist can turn you into someone you don't want to be.
Narcissists are "little" people who demand to be treated like royalty. With my mother, a trip to the grocery store was sure to create a good serving of drama. You see, mother didn't think she had to wait in line like the other customers. She would badger me and the cashiers non-stop about having to wait in line. The sense of entitlement is always a big thing with narcissists. They truly believe they are not like others. They expect to be treated as "special" while viewing those around them as irrelevant nothings or "less than them" or as their slaves. Mother would try to pit me and my other family members against each other and I'm sorry to report that it did work with a few of them. Some of my family members listened to mothers lies and I have not had them in my life for many years. The slander, lies, and gossip was never ending.
Now getting back to the elderly narcissist: Around 8 years ago I finally got better at dealing with my mother. I remember the day when the Lord said to me: "Don't Fear Her", but stand up to her and tell her when she is treating you and others wrong".
I started doing that and most of the time it worked. She got the picture pretty quick that I did not want to listen to her gossip and I would defend those she abused. All of my life she had cut down my dad and she treated him so horrible. One day while she was on a full-tilt bashing session of him I told her, "Mom, I am not coming to see you anymore if you EVER talk bad about dad again. He takes care of you and loves you and you should not be treating him the way you do". She turned her head away, full of anger that I would dare tell her what to do. Her silent treatment went on for a good ten minutes but I will tell you this, she didn't run him down any more after that, at least not to me. I'm sure that everyone else she saw after I finally stood my ground got a double portion of her criticisms of my dad though. I started to stand up for myself and others when I was around my mother from the very day that God got through to me.
As the years went by, mother grew more dependent on me because I was her only care giver. All of the other family members she had alienated through years of abuse and through infighting and trying to manipulate each other. If you have more than one narcissist in your family, things can get really messy quite frequently. I cannot tell you how many times I almost went no-contact with her because of her behavior. To this day I have stayed in contact with her and have taken care of her needs. Recently I was having a discussion with another family member about mother. I had said that she seems "better" than she used to. They told me that they believe that if she were younger, and less dependent, she would be her same critical and narcissistic self. They said that because she is old and dependent upon others that has seemed to make an improvement in how she treats (some) people now. They believe she has NOT change one iota and if given a chance, her sting, like that of a scorpion, is still just as lethal as it ever was. I tend to agree with them. First off, she is more docile and less malicious when I am in her presence because she knows I won't allow her behavior. And who does she really have but me? She knows my limit and if I see her act out I will call her on it. Narcissists know who the push-overs are. They know who they can fool and who will stand their ground. So in conclusion, I believe that many elderly narcissists tend to put on an act. They seem like they have improved in their behavior, but not without reason. They are dependent on others to such a degree that they must curb their nasty behavior or else they would suffer. I grew up seeing how my mother treated those who had something to offer her. If you had nothing to offer her, she had no use for you. This is very sad and unsettling but it is right on the money. Narcissists are users and abusers. It is their way or the highway. They treat their children like tools. Our feelings don't matter. When God got through to me, my mother would attempt to belittle me as always but I would call her on it. What would she say every time? "You're just too sensitive". She would apologize for nothing, you see she was never wrong. She was the queen and everyone else's hopes, needs, time, was irrelevant. It is a sick game that narcissists play and make no mistake, by believing that your elderly narcissist is all better since they've grown older is dangerous. Within the frail little old lady there is still most likely a scorpion ready to strike out at any new prey. Don't let down your guard if you must spend time with them.